The invention pertains to methods of patterning materials, such as, for example, methods of patterning layers associated with photomasks, and methods of patterning layers associated with semiconductor substrates. The invention also pertains to photomask constructions.
Photolithography is commonly used during formation of integrated circuits on semiconductor wafers. More specifically, a form of radiant energy (such as, for example, ultraviolet light) is passed through a radiation-patterning tool and onto a semiconductor wafer. The radiation-patterning tool can be, for example, a photomask or a reticle, with the term xe2x80x9cphotomaskxe2x80x9d being sometimes understood to refer to masks which define a pattern for an entirety of a wafer, and the term xe2x80x9creticlexe2x80x9d being sometimes understood to refer to a patterning tool which defines a pattern for only a portion of a wafer. However, the terms xe2x80x9cphotomaskxe2x80x9d (or more generally xe2x80x9cmaskxe2x80x9d) and xe2x80x9creticlexe2x80x9d are frequently used interchangeably in modern parlance, so that either term can refer to a radiation-patterning tool that encompasses either a portion or an entirety of a wafer. For purposes of interpreting the claims that follow, the term xe2x80x9cphotomaskxe2x80x9d will be utilized to encompass both radiation-patterning tools that define a pattern for an entirety of a wafer (i.e., the tools traditionally referred to as masks), and radiation-patterning tools that define a pattern for only a portion of a wafer (i.e., the tools traditionally referred to as reticles).
Radiation-patterning tools contain light restrictive regions (for example, totally opaque or attenuated/half-toned regions) and light transmissive regions (for example, totally transparent regions) formed in a desired pattern. A grating pattern, for example, can be used to define parallel-spaced conductive lines on a semiconductor wafer. The wafer is provided with a layer of photosensitive resist material commonly referred to as photoresist. Radiation passes through the radiation-patterning tool onto the layer of photoresist and transfers the mask pattern to the photoresist. The photoresist is then developed to remove either the exposed portions of photoresist for a positive photoresist or the unexposed portions of the photoresist for a negative photoresist. The remaining patterned photoresist can then be used as a mask on the wafer during a subsequent semiconductor fabrication step, such as, for example, ion implantation or etching relative to materials on the wafer proximate the photoresist.
Advances in semiconductor integrated circuit performance have typically been accompanied by a simultaneous decrease in integrated circuit device dimensions and a decrease in the dimensions of conductor elements which connect those integrated circuit devices. The demand for ever smaller integrated circuit devices brings with it demands for ever-decreasing dimensions of structural elements on radiation-patterning tools, and ever-increasing requirements for precision and accuracy in radiation-patterning with the tools.
It would be desirable to develop improved methods for forming decreased circuit device dimensions for integrated circuit devices, and to develop improved methods for forming radiation-patterning tools.
In one aspect, the invention encompasses a method of patterning a mass of material. A beam of activated particles is formed proximate a surface of the mass of material, and a deposit is formed on the surface with the beam of activated particles. The beam is displaced relative to the mass to form a pattern of the deposit across the surface of the mass. The mass is then etched while using the deposit as an etch mask. In particular aspects of the invention, the mass of material can be associated with a radiation-patterning tool, such as, for example, a photomask. In other aspects of the invention, the mass of material can be associated with a semiconductor substrate.
The invention also encompasses a photomask construction comprising a substrate, and a patterned material over the substrate. The patterned material covers some regions of the substrate, and leaves other regions not covered. A layer is on the patterned material, but not over the regions of the substrate that are not covered by the patterned material. The layer comprises carbon as a majority component.